How do I convert drop down sting info to values?

How do I convert drop down sting info to values?

Hello all. I really need some help, I am trying to get the following code to turn a set of drop down numbers to formulate as a sum. However I keep getting multiple error messages. I have tried the following variations:

(Risk_Score_1_5.toLong()  +  Return_Score_1_5.toLong()  +  Time_to_Implement_Score.toLong()  +  Cost_Score.toLong())

(input.Risk_Score_1_5.toLong()  +  input.Return_Score_1_5.toLong()  +  input.Time_to_Implement_Score.toLong()  +  input.Cost_Score.toLong())

I have also tried the .toNumber() and the .Tonumber() with errors. Help!